The present invention relates to a technique to conduct radio or wireless communication.
As a technique for a wire Local Area Network (LAN) in which one physical LAN is subdivided into a plurality of virtual LANs (VLANs), there exists a technique in which a VLAN tag (to be simply referred to as a tag hereinbelow) stipulated by IEEE802.1Q is added to a packet to identify, according to the tag, an LAN to which the packet belongs.
There also exists a technique to implement, by use of a relay or repeater (also an access point to be abbreviated to as AP hereinbelow; reference is to be made to JP-A-2003-60656). According to JP-A-2003-60656, there exists a plurality of access points (to be referred to as interconnecting access points hereinbelow) to interconnect a wire LAN and a radio LAN to each other and a plurality of access points (to be referred to as radio access points hereinbelow) to relay data in a radio LAN. Each AP keeps therein a combination table including combinations of tags and unique IDentifiers (IDs) such as an MAC address and an IP address of terminals which conduct communication. As a result, it is possible for even a terminal which cannot directly communicate with an interconnecting AP to communicate via a radio AP with the interconnecting AP as well as with the VLAN in the radio LAN.